Lighting fixtures which are suspended from drop ceilings have well known applications in commercial, industrial, and institutional buildings. These lighting fixtures may include both primary lamps which are normally illuminated, and secondary lamps which can be lit in the event power is interrupted to the primary lamp. See, for example, U.S. Pat. No. 3,860,829 to Fabbri, which discloses a fluorescent lighting fixture having an auxiliary bulb for use as an emergency light. Similarly, U.S. Pat. No. 4,890,200 to Mandy discloses a down lighting system for elevators which includes standard and emergency lights. Still further, U.S. Pat. No. 4,451,762 to Forte et al. discloses a control circuit and system for providing emergency lighting from a single electrical power source.
Conventional lighting fixtures such as those referenced above have historically incorporated rigid mounting structures for the primary and secondary lamps to address known mechanical and thermal operational requirements. These structures, however, impede access to the lamps and thus hinder routine lamp replacement While openings have been designed to provide access to the lamps, such openings have tended to be too large to be aesthetically appealing--particularly in fixture designs where the primary and secondary lamps are mounted within light transmissible enclosures. In such cases, the enclosures are also not supported by the fixture during lamp replacement, thus requiring additional time and labor during maintenance.